Refuse incineration facility including material crusher and melt burner

ABSTRACT

There are provided a pretreatment facility (1) and a incineration/melting facility (2). In the incineration/melting facility, an incineration chamber (3) and a melting chamber (5) are integrally formed through a partition wall (7) so that incineration residue can be continuously transferred. Fine crushed material finely crushed by the pretreatment facility (1) is supplied as fuel to a burner (4). This enables it to obtain melting heat source from waste, and to efficiently treat the waste at a low cost by directly superheating and melting non-cooled incineration residue from the incineration chamber (3).

FIELD OF THE INVENTION

The present invention relates to a refuse incineration facility forcontinuously performing incineration of refuse and melting ofincineration residue.

BACKGROUND OF THE INVENTION

A vertical moving bed furnace has been conventionally known as anincinerator which can continuously perform incineration of refuse andmelting of incineration residue such as incineration ash produced fromincineration. It feeds waste from the top, supplies oxidant (air oroxygen enriched air) into the bottom, and burns waste at the lower partof the fluidized bed and melt residue with heat of its combustion.

However, in the vertical moving bed furnace, since the waste and theoxidant constitute counterflow, and pyrolysis gas generated from thewaste flows out upward together with exhaust gas, temperature is low ina melting chamber at the bottom of furnace, so that the residue cannotbe burnt only with heat value generated from burning of the waste. Thus,coke is fed as pilot fuel to provide ventilation effect as well to meltresidue with heat obtained from the coke. Therefore, coke which isvaluable resource is used, so that there is a problem that the disposalcost is increased.

DISCLOSURE OF THE INVENTION

The present invention is intended to provide a refuse incinerationfacility which can dispose waste at a high efficiency, and reduceincineration cost.

To attain the object, the refuse incineration facility of the presentinvention comprises a pretreatment facility for pretreating waste, andan incineration/melting facility for heating and incinerating the wastetreated by the pretreatment facility, and then for continuously meltingits residue: said pretreatment facility comprising a coarse crusher forcrushing the waste; a coarse crushed material classifier for classifyinglight crushed material mainly consisting of combustible and heavycrushed material containing much noncombustible from the coarse crushedmaterial crushed by the coarse crusher; a recyclable separator forseparating and removing recyclable metals from the heavy crushedmaterial; and a fine crusher for further crushing light crushed materialdischarged from the coarse crushed material classifier; saidincineration/melting facility comprising an incineration chamber forheating and incinerating the material to be incinerated; a meltingchamber formed integrally with the incineration chamber, being capableof continuously transferring incineration residue generated in theincineration chamber from the incineration chamber, and having a burner;fuel supply means for introducing part or all of the fine crushedmaterial crushed by the fine crusher into the burner in the meltingchamber; and crushed material supply means for introducing the heavycrushed material separated by the recyclable separator and remainingfine crushed material crushed by the fine crusher into the incinerationchamber.

In the pretreatment facility with the above arrangement, after the wasteis coarsely crushed by the coarse crusher, the coarse crushed materialis fed to coarse crushed material separator and the recyclableseparator, and separated into light crushed material mainly consistingof combustible and the heavy crushed material containing muchnoncombustible by the coarse crushed material separator. Then, the heavycrushed material is fed to the recyclable separator where recyclablemetals are separated and removed. Thereafter, heavy separated waste isfed to the incineration chamber of the incineration/melting facilitythrough the crushed material supply means. In addition, light crushedmaterial is fed to the fine crusher where it is further crushed. Part orall of it is fed to the burner in the melting chamber through the fuelsupply means, and the remainder is fed to the incineration chamberthrough the crushed material supply means for burning and incineration.Then, in the incineration chamber, the heavy crushed material and theremaining fine crushed material are heated and burnt, and theincineration residue is continuously fed from the incineration chamberto the melting chamber. Then, in the melting chamber, it is heated andmelted by the burner which uses part or all of the fine crushed materialas fuel, reduced for volume and rendered harmless.

With the above arrangement, since waste pretreated and finely crushed isused as fuel for the burner, operating cost can be significantlyreduced. In addition, since the incineration chamber is constructedintegral with the melting chamber so that the incineration residue canbe continuously transferred from the former to the latter, theincineration residue is not once cooled and then heated again as in aseparate type, so that loss of heat is reduced and operation can beefficiently performed. Furthermore, since the incineration chamber isintegrally constructed with the melting chamber, the entire facility canbe made compact.

In addition to the above arrangement, a classifier for material to beincinerated is provided at the discharge side of the fine crusher. Whilethe fuel supply means is provided at the discharge side of the finegrain crushed material of the classifier, the crushed material supplymeans is provided at the discharge side of coarse grain crushedmaterial. The classifier enables it to stably feed only classified finegrain crushed material to the burner as fuel, so that the burner caneffect stable combustion.

Still further, in addition to the above arrangement, an oxygen enrichedair supply unit is provided for supplying oxygen enriched air ascombustion air for the burner. Using oxygen enriched air as combustionair for the burner, it becomes possible to perform suspended combustionof crushed material with low heat value and crushed material withrelatively large crushed area, so that it can be contemplated to performcombustion at a higher temperature, to stabilize flame, and to improvecombustion rate.

Still further, in addition to the above arrangement, a fire grate of theincineration chamber and the hearth of the melting chamber theincineration/melting facility are downward inclined and caused tocontinue to the downstream. This enables it to transfer the incinerationresidue to the melting chamber without lowering its temperature, and topreheat incineration residue by utilizing the gas for the burner, sothat combustion and melting can be efficiently performed.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram of the refuse incineration facility accordingto an embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Referring to FIG. 1, there are provided a pretreatment facility 1 forpretreating waste, and an incineration/melting facility 2 for heatingand incinerating the waste treated by the pretreatment facility 1 andthen continuously melting and processing its residue.

The incineration/melting facility 2 is integrally provided with anincineration chamber 3 for combusting the crushed material fed from ahopper 3a on a fire grate 3b, and a melting chamber 5 for heating andmelting incineration residue discharged from the incineration chamber 3with a fluff burner 4 which is an example of a burner. Then, molten slagmelted in the melting chamber 5 is fed into a slag cooling chamber 6 toproduce granulated slag. In addition, the incineration chamber 3 and themelting chamber 5 are partitioned at their upper sections with onepartition wall 7. Then, disposed on the lower section of the partitionwall 7 are the fire grate 3b of the incineration chamber 3 downwardinclined from the upstream to the downstream and the hearth 5a of themelting chamber 5 so that the incineration chamber 3 communicates withthe melting chamber 5. The fire grate 3b of the incineration chamber 3is constituted to be movable by alternately arranging in the lateraldirection a row of fixed fire grates and a row of movable fire gratesreciprocated in the feeding direction. In addition, provided on thelower section of the hopper 3a is a crushed material pusher unit 32 forsupplying the crushed material fed through the hopper 3a onto the firegrate 3b. Therefore, the incineration residue generated in theincineration chamber 3 is directly and continuously supplied to themelting chamber 5 without lowering temperature by utilizing feedingforce of the fire grate 3b and the crushed material pusher unit 32, andthe gravity.

In a case where it is difficult to continuously transfer theincineration residue to the melting chamber 5 by the feeding force ofthe fire grate 3b and the crushed material pusher unit 32, and thegravity, as shown by phantom lines, an incineration residue forcedpusher unit 31 is provided at a step formed between the fire grate 3band the hearth 5a of the melting chamber 5, the pusher unit 31comprising an air cylinder 31a, and a pusher block 31b extended andretracted by the air cylinder 31a.

Combustion gas a at a high temperature generated by the melting powderburner 4 to heat the incineration residue, is fed to the incinerationchamber 3 side to preheat the incineration residue being transferred,and then discharged together with exhaust gas from the incinerationchamber 3, and, at that time, heat is recovered by a boiler heatexchanger 8.

The pretreatment facility 1 comprises a coarse crusher 11 for coarsecrushing waste to about 50-80 mm square, a dryer 12 (disposed asrequired) for the coarse crushed material crushed by the coarse crusher11, an air gravitation separator 13 which is an example of a coarsecrushed material separator for separating the coarse crushed materialwith wind force into light crushed material mainly consisting ofcombustible and heavy crushed material containing much non-combustible,a recyclable material separator 14 for separating and removingrecyclable metals such as aluminum and iron by utilizing a magnet orspecific gravity, a fine crusher 15 for further finely crushing thelight crushed material discharged from the air gravitation separator 13,and a classifier unit 16 (disposed as required) for classifying the finecrushed material crushed by the fine crusher 15 into fine grain crushedmaterial (fluff fuel) with size of 5 mm square or less which can be usedas fuel for the fluff burner 4 and coarse grain crushed material withsize exceeding it.

Then, a fuel supply pipe (fuel supply means) 17 for pneumaticallytransporting the fine grain crushed material to the fluff burner 4 asfuel is connected to the fine grain crushed material discharge side ofthe classifier 16, while a coarse grain crushed material supply pipe(crushed material supply means) 18 for pneumatically transporting wasteinto the hopper 3a of the incineration chamber 3 is connected to thecoarse grain crushed material discharge side. The coarse grain crushedmaterial supply pipe 18 is provided with a circulating pipe forreturning the coarse grain crushed material to the classifier 16, asrequired.

It may be possible to directly supply the fine crushed material crushedby the fine crusher 15 to the fluff burner 4 through a fuel supply pipe17', or to directly supply it from the fine crusher 15 to the hopper 3aof the incineration chamber 3 through the coarse grain crushed materialsupply pipe 18.

In addition, in a case where the fine crusher 15 has a capability ofcrushing most of the fine crushed material crushed by it to fine graincrushed material (fluff fuel) with size of 5 mm square or less which canbe used as fuel for the fluff burner 4, all fine crushed material may besupplied to the fluff burner 4 through the supply pipe 17'.

The fluff burner 4 is connected with a combustion air pipe 21 forsupplying combustion air from an air supply unit 20. In addition, thecombustion air pipe 21 is connected with an enriched air pipe 23, sothat oxygen enriched air of which oxygen concentration is enhanced byabout 30% can be supplied from an enriched air pipe 23 to the fluffburner 4 through the combustion air pipe 21 by an oxygen enriched airgenerator 22.

With the above arrangement, collected waste is first fed to thepretreatment facility 1, and primarily crushed to size of about 50-80 mmsquare by the coarse crusher 11. Then, it is transferred to the airgravitation separator 13 after dried by the dryer 12 or without dried,where the coarse crushed material is separated into heavy crushedmaterial and light crushed material. The heavy crushed materialseparated here or that directly fed from the coarse crusher 11 istransferred to the recyclable waste separator 14 where recyclable metalsare separated and removed. Thereafter, it is fed to the hopper 3a of theincineration chamber 3 through a heavy crushed material supply line(crushed material supply means) 19.

The light crushed material separated by the air gravitation separator 13is fed to the fine crusher 15 for secondary crushing so that it isfurther finely crushed. Then, the fine crushed material is classified bythe classifier 16, and fine grain crushed material (fluff) of 5 mmsquare or less is fed to the fluff burner 4 through the fuel supply pipe17. In addition, coarse grain crushed material larger than 5 mm squareis transferred to the hopper 3a through the coarse grain crushedmaterial supply pipe 18, and fed into the incineration chamber 3.

If no classifier 16 is provided, the fine crushed material is dividedinto predetermined volume, required volume is supplied to the fuelsupply pipe 17', and remaining volume is supplied to a coarse graincrushed material supply pipe 18'.

In addition, if most of the fine crushed material is fine grain crushedmaterial (fluff) of size of 5 mm square or less, all of the fine crushedmaterial may be transferred from the fuel supply pipe 17' to the fluffburner 4.

The crushed material fed to the incineration chamber 3 through thehopper 3a is heated, burnt and incinerated to produce incinerationresidue. The incineration residue is directly fed from the fire grate 3bto the hearth 5a of the melting chamber 5 by the feeding force of thefire grate 3b and the crushed material pusher unit 32 and the gravity.Then, it is heated and melted by the fluff burner 4. Then, molten slagis fed into the slag cooling chamber 6 for water cooling to producegranulated slag. In this case, the combustion gas a in the meltingchamber 5 is fed from the hearth 5a to the fire grate 3b to preheat theincineration residue before discharged together with exhaust gas fromthe incineration chamber 3, and heat is recovered by the boiler heatexchanger 8. Steam obtained from the boiler heat exchanger 8 isintroduced into a steam turbine in a generator 9 for electric powergeneration. In addition, the exhaust gas is discharged through anexhaust gas processing unit 10.

Then, the fluff burner 4 is supplied with pilot fuel such as LPG orheavy oil which is combusted at start-up or when quantity of heat fromthe fluff fuel is insufficient, and with the fine grain crushed material(fluff) of 5 mm square or less from the fuel supply pipe 17 andcombustion air from the combustion air supply pipe 21 for combustion. Inaddition, if it is necessary, enriched air is supplied from the oxygenenriched air generator 22 to the fluff burner 4. Using enriched air forcombustion of which oxygen concentration is enhanced to about 30%enables it to combust fine crushed material of about 5 mm square whileconventionally only those of 1 mm square or less can be used as flufffuel for the fluff burner. This also enables it to perform combustion ata high temperature, to stabilize flame, and to improve combustionefficiency. Furthermore, use of the enriched air for combustion enablesit to reduce amount of exhaust gas by about 30%, so that it is possibleto improve heat efficiency, and to reduce the size of exhaust gastreatment facility.

With the above embodiment, since fine grain crushed material (fluff)which is waste finely crushed by the coarse crusher 11 and the finecrusher 15 is used as fuel for the fluff burner 4, the operating costcan be significantly saved. In addition, since the fire grate 3b of thecombustion chamber 3 and the hearth 5a of the melting chamber 5 arearranged to be continuous, and downward inclined, incineration residueis continuously transferred by feeding force of the incineration chamber3 and its own weight. Accordingly, since it is not necessary to heat theincineration residue again after it is cooled as in the separate type,heat energy is less lost, so that operation can be performed at a highefficiency. In addition, since the incineration chamber 3 and themelting chamber 5 are integrally constituted with the partition wall 7separating them, the entire facility can be made compact.

In addition, since only fine grain crushed material which is finecrushed material crushed by the fine crusher 15 classified by theclassifier 16 is used as fuel for the fluff burner 4, more stablecombustion can be performed.

Furthermore, use of oxygen enriched air as combustion air for the fluffburner 4 enables it to perform suspended combustion of crushed materialwith low heat value and those with relatively large crushed area, sothat combustion at higher temperature, stabilization of flame, andimprovement of combustion efficiency can be attained.

Although the above embodiment has been described for a refuseincineration facility which heats and incinerates waste before itsresidue is "continuously" melted and treated, the term "continuous"includes a functional operation of direct feeding from the fire grate 3bto the hearth 5a, but also includes a temporal and modal operationwhere, instead of heating residue which is once cooled as in the priorart, residue is fed in a state with high temperature for furtherheating.

We claim:
 1. A refuse incineration facility comprising a pretreatmentfacility (1) for pretreating waste, and an incineration/melting facility(2) for heating and incinerating the waste treated by the pretreatmentfacility, and then for continuously melting its residue,saidpretreatment facility (1) comprising:a coarse crusher (11) for crushingthe waste; a coarse crushed material classifier (13) for classifyinglight crushed material mainly consisting of combustible and heavycrushed material containing much noncombustible from the coarse crushedmaterial crushed by the coarse crusher; a recyclable separator (14) forseparating and removing recyclable metals from the heavy crushedmaterial; and a fine crusher (15) for further crushing light crushedmaterial discharged from the coarse crushed material classifier; saidincineration/melting facility (2) comprising:an incineration chamber (3)for heating and incinerating the material to be incinerated; a meltingchamber (5) formed integrally with the incineration chamber (3), beingcapable of continuously transferring incineration residue generated inthe incineration chamber from the incineration chamber, and having aburner (4); fuel supply means (17) for introducing at least a portion ofthe fine crushed material crushed by the fine crusher into the burner(4) in said melting chamber; and crushed material supply means (18, 18',19) for introducing the heavy crushed material separated by therecyclable separator (14) and any remaining fine crushed materialcrushed by the fine crushed (15) into the incineration chamber (3). 2.The refuse incineration facility as set forth in claim 1, wherein aclassifier (16) for material to be incinerated is provided at thedischarge side of the fine crusher;said classifier (16) being connectedto the fuel supply means (17) at the discharge side of fine graincrushed material, and connected to the crushed material supply means(18) at the discharge side of coarse grain crushed material.
 3. Therefuse incineration facility as set forth in claim 1 furthercomprisingoxygen enriched air supply unit (22, 23) for supplying oxygenenriched air as combustion air for the burner (4).
 4. The refuseincineration facility as set forth in claim 2 further comprisingoxygenenriched air supply unit (22, 23) for supplying oxygen enriched air ascombustion air for the burner (4).
 5. The refuse incineration facilityas set forth in any of claims 1 through 4, whereinthe fire grate (3b) ofthe incineration chamber (3) the hearth (5a) of the melting chamber (5)are continued the downstream with downward inclination in theincineration/melting facility (2).